Water flow

“ Owing to a flow of upland water down a river the ebb lasts longer than the flood tide by a period, increasing in length as the distance from the mouth of the river increases; and, similarly to the sea, the current may continue to run down a river after the tide has turned and the level of the water is rising. ”

“ There are both rivers of wind and rivulets of wind, although their branches are exactly the reverse of water currents: for in the air it is the rivulets which flow out of the rivers, and the smaller rivers which flow out of the great streams instead of falling into them. ”

“ Waters flow incessantly, they flow day and night until they merge together in a large ocean. Similarly, the true teaching of our fathers, grand-fathers, and grand-grand-fathers from the beginning of the world was flowing without stop for us. ”

“ Every considerable addition to its water wells up, and soaks its very surface; and that which is added after it is already brim full, must flow off over the surface, or lie in puddles upon it. Evaporation is a slow process, and it becomes more and more slow as the level of the water recedes from the surface, and is sheltered, by the overlying earth, from the action of sun and wind. ”

“ The chief point of supply is at the very head of the flowing water. The rain which falls on material that has been disintegrated by weathering, begins after it has saturated the immediate surface to flow off. ”

“ When rain-water falls on the earth it either sinks into the ground until it reaches an impervious layer, where it collects as a subterranean pool, forming a well, or continues to flow underground until it finally emerges at the surface as a spring ”

“ As the gentle waves ebb and flow on the shore he follows them back and forth, keeping close to the edge, where the food which is washed out of the sand is most abundant and the aeration of the water most perfect. ”

“ This is because water, in flowing from place to place, expends force in overcoming the friction of the pipes and the resistance of the air. The greater the distance traversed by the water in its journey from reservoir to faucet, the greater the waste force and the less the final flow. ”

“ Where a stream exists in the school locality it should be made the text for the lessons on the flow of rivers, and the action of running water upon the surface of the land. The portion of the rain that sinks underneath the surface is less easily followed. ”

“ At the flow of the tide, the fresh water is raised, as it were, in a single mass by the salt water which flows in, and which ascends the bed of the river, while the fresh water continues to flow towards the sea.—Mr. ”

“ The rain falls down in little drops, some of which soak into the ground, while others make rivulets that run into brooks that in time join the rivers that flow into the sea. Much of the water that soaks into the ground finds its way again to the surface in springs that feed the brooks and keep them alive when no rain is falling. ”

“ And yet most of us accept as a matter of course the stream which gushes from our faucet, or give no thought to the ingenuity which devised a means of forcing water upward through pipes. Despite the fact that water flows naturally down hill, and not up, we find it available in our homes and office buildings, in some of which it ascends to the fiftieth floor; and we see great streams of it directed upon the tops of burning buildings by firemen in the streets below. ”

“ Watched thy clear blue waters as they slowly pass by,
Reflecting true pictures of the clouds in the sky.
So deep is thy bottom and so broad is thy stream,
Thy volume is greater than thy looks make it seem,
Tho slow is thy current, great force there is in it,
Moving a million tons of water each minute.{120}
Many are the sources that provide the supply,
That keeps this great river from ever running dry,
The inflow and outflow do so nearly conform,
That the river’s level is very uniform. ”

“ Stand here by my side and turn, I pray,
On the lake below thy gentle eyes;
The clouds hang over it, heavy and gray,
And dark and silent the water lies;
And out of that frozen mist the snow
In wavering flakes begins to flow;
Flake after flake
They sink in the dark and silent lake. ”

“ The rainfall may be divided into three parts: the first DRIES UP, being discharged into the air by evaporation either directly from the soil or through vegetation; the second RUNS OFF over the surface to flood the streams; the third SOAKS IN the ground and is henceforth known as GROUND or UNDERGROUND WATER.
THE DESCENT OF GROUND WATER. Seeping through the mantle of waste, ground water soaks into the pores and crevices of the underlying rock. All rocks of the upper crust of the earth are more or less porous, and all drink in water. ”

“ Fresh water may, farther, be divided into atmospheric, which includes hail, rain, and snow-water, and also dew; stagnant, such as that of lakes, ponds, and marshes; and running, which comprehends spring, well, and river-water. ”

“ Now, the power of this moving water is a mighty wide-spread agent of change in the physical condition of the globe. For wherever water is in motion over the surface of the land, whether it be a rippling stream, or a mountain torrent, or a majestic river, it is surely wearing away the channel through which it flows, and carrying along in its course particles of clay, or sand, or gravel. ”

“ These springs feed the streams and rivers which carry the water back again to the sea. It is owing to this continuous circulation of water that the sea does not overflow, or the rivers dry up. Moreover, those damp exhalations supply the air with that moisture which is necessary to the life of men and beasts, and to the growth of plants. One thing more. You know that water turns foul when it remains for some time without being stirred. How is it that though it is shut in one place, the water of the sea never turns foul? ”

“ Can you imagine these water-particles, just above any pond or lake, rising up and getting entangled among the air-atoms? They are very light, much lighter than the atmosphere; and so, when a great many of them are spread about in the air which lies just over the pond, they make it much lighter than the layer of air above, and so help it to rise, while the heavier layer of air comes down ready to take up more vapour. ”

“ Thus we learn that it is the warmth of the sun that has made the water boil. If you visit the water-works you will see great reservoirs. In some cases they have been filled by a river, sometimes the water is pumped from a15 deep well in the ground, sometimes it is the surface-water caught on a mountain side. Whatever be the immediate source of our water supply, the real origin is to be sought, not in the earth beneath, but in the heavens above. All the water we use day by day has come from the clouds. ”

“ The action of water in stream and sea, in springs and wells, is evident to all; but the activity of ground water—that is, rain water which sinks into the soil and remains there—is little known in general. ”

“ The sun is changing the surface water into steam which rises into the sky to form a part of another bank of clouds. The earth has soaked up quantities of the water that fell. If we followed the racing currents in the gullies we should find them pouring into sewer mains at various points, and from these underground pipes the water is conducted to some outlet like a river. All of the streams are swollen by the hundreds of brooks and rivulets that are carrying the surface water to the lowest level. ”

“ In the waters it occurs as a mechanical mixture which is brought about as the rain forms and falls in the air, as the streams flow to the sea, and as the waves roll over the deep and beat against the shores. In the realm of the waters, as well as on the land, the air is necessary for the maintenance of all animal forms ”

“ But it is observable that the waters of lakes and ponds stand immovable, because the air about them stagnates immovable and admits of no vacuity. For the water on the surface of lakes and seas is troubled and fluctuates as the air is moved, it following the motion of the air, and moving as it is moved. ”

“ This drains off from the surface, forming rills, which collect as they descend, by their own weight, into the lowest channels of the ground, and form into streams and rivers, and back into the sea comes the water which the air had taken away, with this difference, that it is free from salt and fit for the many uses to which fresh water alone can be applied; when the vapour rises from the sea, none of the saline matters rise with it, for, although the water is volatile, yet they are not, and this is the whole source of fresh water. ”

“ In connection with the question of absorption and filtration, it is interesting to investigate the movements of water in the ground. The natural tendency of water, in the soil as well as out of it, is to descend perpendicularly toward the center of the earth. ”

“ Wherever the sun-waves touch the rivers, ponds, lakes, seas, or fields of ice and snow upon our earth, they carry off invisible water-vapour. They dart down through the top layers of the water, and shake the water-particles forcibly apart; and in this case the drops fly asunder more easily and before they are so hot, because they are not kept down by a great weight of water above, as in the kettle, but find plenty of room to spread themselves out in the gaps between the air-atoms of the atmosphere. ”

“ The instant the water reaches the earth, it is hurried away toward the sea, and unless some agency delays the run-off, the rivers would naturally contain water only on the rainy days and a little while after. ”

“ Were the salts of the sea lighter instead of heavier than the water, they would, as they feed the winds with moisture for the cloud and the rain, remain at its surface, and become more niggardly in their supplies, and finally the winds would howl over the salt-covered sea in very emptiness, and, instead of cool and refreshing sea-breezes to fan the invalid and nourish the plants, we should have the gentle trade-winds coming from the sea in fitful blasts of parched, and thirsty, and blighting air. ”

“ Next it increases in its volume and its power, now rushing rapidly, now moving along in deep and tranquil water, until it swells into a bold stream, coursing its way over the shallows, dashing through the impeding rocks, descending in rapids swift as thought, or pouring its boiling water over the cataract. ”

“ A stream is water falling down hill with a velocity depending upon the inclination of its bed. As it falls it acquires momentum and, hence, energy; and thus a mountain stream, suddenly swollen by rain or melting snow, will tear away masses of rock and sweep everything before it. Nothing can look softer or more harmless than a calm sea, but if the wind sweeping over its surface puts the water in motion, it strikes upon the shore with terrific force ”

“ It is scarcely necessary for me to observe that water may come down a hill, although it never goes up. Rain, snow, dew, and generally all the vapors that fall from the atmosphere, furnish the enormous masses of water that are constantly flowing into the sea. ”

“ The union of a number of springs forms a river. The waters as they run, exposed to the sun, air, and wind, are continually evaporating. Hence in travelling one may often see where a river runs, by a long blueish mist over it, though we are at such a distance as not to see the river itself. The quantity of this evaporation is greater or less, in proportion to the surface exposed by the same quantity of water to those causes of evaporation. While the river runs in a narrow confined channel in the upper hilly country, only a small surface is exposed; a greater as the river widens. ”

“ As the layers of earth or rock, of which the {82}crust of the earth is made up, do not run level, or horizontal, but are tilted and tipped in all directions, this rain water soaks down until it reaches one of these sloping layers that is so hard, or tough, as to be waterproof, and then runs along over its surface in a sort of underground stream. ”

“ But we see in the professor's experiments the dawn of more new beauties, and the appearance of other exquisite compensations, which, in studying the 'wonders of the deep,' we have so often paused to contemplate and admire:—As the trade- wind region feeds the air with the vapour of fresh water, the process of evaporation from the sea is checked, for the water-which remains, being salter, parts with its vapour less readily ”

“ The vast volume of pent-in water meeting all manner of submerged obstacles dashes in zigzag from shore to shore, cannoning off walls of rock until the whole gorge becomes one rushing, gyrating mass of angry water. ”

“ Fastening our attention for the moment on surface water waves, the first question we shall ask ourselves is—What is a wave? If we take our station on a high cliff looking down on the sea, on some clear day, when the wind is fresh, we see the waves on its surface like green rounded ridges racing forward, and it appears at first sight as if these elevations were themselves moving masses of water. ”

“ In this way the sun-waves and the air carry off water everyday, and all day long, from the top of lakes, rivers, pools, springs, and seas, and even from the surface of ice and snow. Without any fuss or noise or sign of any kind, the water of our earth is being drawn up invisibly into the sky. ”

“ These waves are raised by the rapidity of the water's descent, which, rushing downward at a rate of twenty-five miles an hour, is lashed to fury by the air, just as a rushing air raises the still waters of a lake or ocean. And the very swiftness of the descent is indicated by, and makes inevitable, the violence of the resisting waves, as we shoot down to the calm waters below the rapids. ”